Histone demethylase JMJD3 regulates fibroblast-like synoviocyte-mediated proliferation and joint destruction in rheumatoid arthritis.

Rheumatoid arthritis (RA) is an immune-mediated disease with the characteristics of progressive joint destruction, deformity, and disability. Epigenetic changes have been implicated in the development of some autoimmune disorders, resulting in an alteration of gene transcription. Here, we investigated how Jumonji C family of histone demethylases (JMJD3) regulated the proliferation and activation of fibroblast-like synoviocytes (FLSs), which are involved in RA joint destruction and pathologic process. The JMJD3 expression and proliferation markers in RA-FLS were higher than those in healthy-FLS and were upregulated in platelet-derived growth factor (PDGF)-induced FLS. Elevated JMJD3 promoted the proliferation and migration of FLS. Treatment with JMJD3 small interfering RNA or inhibitor glycogen synthase kinase (GSK) J4 led to decreased proliferation and migration of FLS. Interestingly, induction of proliferating cell nuclear antigen (PCNA), a major player of the cell-cycle regulation, was correlated with trimethylated lysine 27 in histone H3 loss around the gene promoters. The knockdown of JMJD3 abolished PCNA expression in PDGF-induced FLS and further inhibited cell proliferation and migration, suggesting that JMJD3/PCNA played a crucial role in aspects of FLS proliferation and migration. In vivo, the ability of GSK J4 to hinder collagen-induced arthritis (CIA) in DBA/1 mice was evaluated. We found that GSK J4 markedly attenuated the severity of arthritis in CIA mice. The therapeutic effects were associated with ameliorated joint swelling and reduced bone erosion and destruction. This study revealed how JMJD3 integrated with epigenetic processes to regulate RA-FLS proliferation and invasion. These data suggested that JMJD3 might contribute to rheumatoid synovial hyperplasia and have the potential as a novel therapeutic target for RA.-Jia, W., Wu, W., Yang, D., Xiao, C., Su, Z., Huang, Z., Li, Z., Qin, M., Huang, M., Liu, S., Long, F., Mao, J., Liu, X., Zhu, Y. Z. Histone demethylase JMJD3 regulates fibroblast-like synoviocyte-mediated proliferation and joint destruction in rheumatoid arthritis.